Automatic shutoff valve for hydraulic transmission systems



H. FIELD, JR 2,428,150 AUTOMATIC SHUT-OFF VALVE FOR HYDRAULIC TRANSMISSION SYSTEMS sepa 3o, 1947.

Filed March 5, 1924;',

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Patented Sept. 30, 1,947

OFFICE AUTOMATIC SHUTOFF- VALVE FOB HY- DRAULIC TRANSMISSION SYSTEMS Howard Field, Jr., Los Angeles, Calif.

Application March 5, 1943, Serial No. 478,138

This invention relates to an automatic shutofi.' valve to be used in connection with hydraulic systems of the type which include a pump. a primary line extending from the pump to one or more devices to be operated hydraulically and a return line extending from the device or devices to the pump. This, brieily, is the type of hydraulic system used in aircraft and occasionally the hydraulic lines will break accidentally or will be broken or severed by gun nre or for other reasons. My automatic shut-o!!` valve is included in the hydraulic system in such a manner that both the primary flow and the return flow pass through my valve. 1f any lines bev come broken or severed between my shut-oil valve and any of the operating mechanisms (such as a hydraulic cylinder or control valve therefor), then my shut-ot! valve will automatically operate and will prevent the loss of fluid in the ilow lines and permit the continued operation of all such devices connected thereto except the particular device with which the connecting lines are ruptured.

An object of my invention is to provide a novel automatic shut-o valve of the character stated which is controlled by the flow of iluid in the return line and if there is no ilow of iluid in this return line, the valve remains closed and the pump cannot force fluid through such lines causing the fluid to be lost.

Another object of my invention is to provide a novel automatic shut-oil? valve in which the ilow of fluid in the primary line actuates a piston, this piston closing the outlet port in the primary ilow', the `piston remaining'in seated or closed position until ilow is established in the return line.

Another object oi' my invention is to provide a novel automatic shut-oil valve in which only a limited amount of iluid is permitted to flow in the primary line until flow is established in the return line.

Another object of my invention is to provide a novel automatic shut-oil.' valve in which a poppet type of valve serves to prevent unlimited flow through the primary line until said valve is unseated by means of ilow in the return line reacting against a piston, said poppet valve being adapted to open whenever ilow in a reverse direction occurs in the primary line due to expansion of fluid or for other reasons.

A feature of my invention is to provide a novel means of unseating a valve in the primary flow line by pressure in the return ilow line, thus opening the circuit in the primary ilow line.

5 Claims. (Cl. 60-52) Another feature of my invention is to provide a valve of the character stated in which there is no accurate concentrlcity required in the valve and release mechanism therefore thereby eliminating accurate machine work and enabling the valve to be produced at a lower cost.

Still another object of my invention is to provide a novel automatic shut-oli valve which is simple in construction, eil'ective in operation and inexpensive to manufacture.

An advantage of my valve is that the ilow can be established through my valve by a manual release in order to clear the lines or to test them.

Other objects, advantages and features of invention will appear from the accompanying drawing, the subjoined detailed description and the appended claims. Referring to the drawing, which is for illustrative Purposes only.

Fig. 1 is a vertical sectional view of my shutoff valve;

Fig. 2 is an end view of the same partly in section; and

Fig. 3 is a diagrammatic view showing one method of connecting the shut-oil valve in a hydraulic system. f'

Referring more particularly to the drawing, my shut-oil? valve I comprises a valve body 2 and a. cylinder 3 which may be an integral part of the body 2 or may be otherwise suitably attached thereto. The valve body 2 includes a primary inlet port 4 into which the primary flow line from the pump extends, shown diagrammatically at 5 in Fig. 3. A primary outlet port 6 is also provided in the body 2 and the primary line extending to the control valves or hydraulic operating mechanism extends from this port, this line is shown diagrammatically at 'I in Fig. 3. A duct 8 extends from the inner end of the cylinder 3 into the port 6. The purpose of this duct will be subsequently described.

A valve 9 is pressed downwardly by the coil spring III onto a seat in the bore I I which also communicates with the outlet port 6. A push rod I2 adapted to contact the lower end of valve 9 extends downwardly into a bore I3 in the body 2. Suitable packing I4 surrounds the push rod I2 to prevent leakage around this push rod. A return ow intake port I5 extends through the body 2 and into the bore I3. An exhaust return port IG also extends through the body 2 and into the bore I3 and is positioned above the port I5, substantially as shown. 'Ihe return ow line I'I is diagrammatically shown in Fig. 3, and this flow line extends into the port I5. The exhaust return flow line I8, also diagrammatically shown 3 in Fig. 3, extends to a reservoir or to the return oi' the pump, all of which is usual and well known in hydraulic systems. As thus far described it might be stated that if any of the lines A`|, II or any of the other lines connecting the control valves or the hydraulic operating mechanism should be broken, either accidentally or by gun ilre, then my control valve will automatically function to prevent the leakage of fluid through such a broken line.

A nut I3 closes the lower end of the bore I3 and pin 20 is slidably mounted in this nut. A hand lever 2| is pivotally mounted on an ear 22, depending from the nut "I3, This hand lever engages the bottom of the pin 20 causing this pin to move upwardly and engage a piston 23 in the bore I3. The push rod I2 engages the upper face of the piston and consequently upward movement of the pin 23 will raise the piston 23 which will raise the push rod I2 which in turn will raise the valve 3 of! of its seat, thus providing a passageway between the inlet port 4 and the outlet port l in the primary flow line and a passage between the intake port I5 and the exhaust port I3 in the return llow lines. A piston 24 is mounted in the cylinder 3 and is pressed towards the outer end of the cylinder by the coil spring 25,

The outer diameter of piston 24 carries a, packing 26 which prevents fluid flowing through the clearance space necessarily existing between the piston and the cylinder due to manufacturing tolerances thus preventing iluid from flowing past the piston. A conduit 23 may be an integral part of the cylinder 3A or may be a separate tube if desired. This conduit 23 is open at one end to the primary intake port 4 and a port 29 connects .the conduit 23 and the outer end of the cylinder 3 enabling l'luld under pressure to act against the outer end of the piston 24 urging this piston inwardly.

Some fluid might leak past the piston 23 and be trapped in the portion ofthe bore I3 above the piston 23 and thus prevent upward movement of the piston. To overcome this dilllculty I provide a relief channel 33 in the piston, this channel being open to the port I6 and permitting any accumulated duid to pass out through this port.

In operating, assuming first that all of the lines are intact and that the valve is completely full of iluid, the pump forces fluid under pressure into the port 4. This iluid then passes through the conduit 28 and the duct 29 and urges the piston 24 inwardly, or towards the right, as

viewed in Fig. l. The inner end of the cylinder 3 is entirely filled with fluid and consequently this inward movement of the piston will cause the fluid contained in the cylinder and on the inward or right hand side of piston 24 to iiow through the duct 3 and thence through the primary outlet port i. This movement of duid in the primary line causes the operating mechanism to function and there is an immediate movement of fluid in the return flow lines. This return iluid passes through the port I5 into the bore I3 lifting the piston 23, which lifts the push rod I2 which lifts the valve 9 against the spring l0. As soon as the valve 9 is unseated a passage is created between the ports 4 and 6 thus, providing free movement of fluid in the primary flow lines. The piston 23is forced upwardly until the port I3 is exposed and a passage is thus provided for the return flow line within my control valve. If any of the lines between my control valve and the operating mechanism should be broken, there would be no fluid pressure available to lift the piston 23 and the valve 9. Consequently, the valve 9 would remain seated. The piston 24 would continue to advance in the cylinder 3 until it reached the stop 21. At this stage of operation no more fluid could be displaced through port B since valve 9 prevents direct flow between port 4 and port 6 and fluid cannot pass piston 24. The only fluid which would be lost would be the small amount which was in the 'cylinder 3 and which was forced out by the inward movement of the piston 24. Once the piston 24 is seated the pump can no longer force additional uid into the system. As soon as the lines are repaired, however, the valve will automatically function as first described and the System will function in the intended manner.

If lt is desired to clear the lines of air or obstructions or to test the lines the handle 2I may be operated to open clear passages through the valve in both the primary and return lines as described above. It is evident that the pin 20 does not have to be exactly concentric with the piston 23 nor the piston 23 exactly concentric with the push rod I2 nor the push rod I2 with the valve 9 in order for the automatic shut-off valve to function as intended. Consequently the machine work necessary to produce the valve can be easily and cheaply made.

As shown in Fig. 3 I have shown a single automatic shut-off valve indicated at 2 with the control valves indicated at 35 and 36 connected respectively to operating cylinders 31 and 38. One

cylinder being connected, for instance, to the flaps and the other to the landing gear of an airplane in the well known manner. These valves 35 and 36, of which there is one such valve for each part of the plane designed to -be operated, are manually controlled. When for example the valve 35 is opened to the system and it is found that the lines connecting such valve to its operating cylinder have become ruptured the whole system fails in operation but if such valve 35 is then closed the remainder of the system becomes operative thereby allowing manipulation of other devices controlled by other operating values.

I claim as my invention:

l. An automatic shut-off valve comprising a valve body having a primary inlet port and a primary outlet port; a chamber communicating at one end with said primary inlet port and at the other end with said primary outlet port; a moveable fluid separating means within said chamber. said body having a return intake. port and a return exhaust port, saidV valve body having a passage between said primary inlet port and said primary outlet port; a valve seat in said passage; poppet valve means engageable with said seat for controlling the flow to said primary outlet port; and means operable by the return fluid pressure to unseat said valve means.

2. An automatic shut-olf valve comprising a valve body having a primary inlet port and a primary outlet port; a chamber communicating at one end with said primary inlet port and at the other end with said primary outlet port; a moveable fluid separating. means within said chamber, said body having a return intake port and a return exhaust port; valve means controlling fluid ow between said primary inlet port and said primary outlet port, including a poppet valve and seat; and means operable by the return fluid pressure to unseat said valve means.

3. In an automatic fluid pressure valve, the combination of: housing means having first and second fluid chambers; first inlet and outlet ports communicating with said rst chamber; second inlet and outlet ports communicating with said second chamber; f lrst valve means in said first chamber movable between a closed position in which'it closes iiuid communication between said first ports and an open position in which it opens fluid communication between said first ports, said first valve means being at all times subjected to the fluid pressure in said first inlet port tending to retain it in said closed position; second valve means in said second chamber between said second ports and adapted to normally close fiuid communication therebetween but movable in response to fluid pressure in said second inlet port to open fluid communication between said second ports; means operatively connecting saidvalve means so that movement of said second valve means is communicated to said first valve means to move said first valve means to said open position; a cylinder communicating at one end with said first inlet port and at the other end with said first outlet port; and piston means in said cylinder adapted to be moved in lresponse to the admission of fluid under pressure into said cylinder from said first inlet port to displace fiuid from said cylinder into said first outlet port.

4. An automatic shut-off valve comprising a, valve body having a primary inlet port, a primary outlet port, a return intake port and a return exhaust port; a chamber communicating at one end with said primary inlet port and at the other end with said primary outlet port; movable means adapted to close communication between said chamber and said primary outlet port disposed within said chamber; valve means controlling iiow between said primary inlet port and said primary outlet port; and means operable by the return fluid flow to open said valve means, said means comprising aV piston normally closing the return exhaust port and'movable by return flow entering the return intake port and a push rod engageable by said piston to open said valve means not later than the opening of said return exhaust port by said piston.

5. In an automatic iiuid pressure valve, the combination of a valve body having first and second fluid chambers, a first inlet port and a first outlet port communicating with said first chamber, a valve seat between said first ports, and a second inlet port and a second outlet port communicating with said second chamber, said body having a wall separating said chambers; a, first valve member in said first chamber adapted to seat on said valve seat to close fluid communication between said first ports, uid pressure in said rst inlet port tending to hold said first valve member in seated position on said valve seat; a second valve member in said second chamber between said second ports and adapted to normally close communication therebetween but movable in response to fluid pressure in said second inlet port to open fluid communication between said second ports, said second valve member having an effective cross-sectional area exposed to fluid pressure in said second inlet port greater than the effective cross-sectional area of said i'lrst valve member exposed to fluid pressure in said first inlet port; a valve stem extending through said wall and adapted to operatively connect said valve members so that said first valve member is unseated in response to movement of said second valve member; a cylinder communicating at one end with said rst inlet port and at the other end with said first outlet port; and piston means in said cylinder adapted to be moved in response to the admission of fluid under pressure into said cylinder from said first inlet port to displace fuid from said cylinder into said first outlet port.

HOWARD FIELD, Jn.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 881,848 Day Mar. 10, 1908 1,045,693 Gillman Nov. 26, 1912 1,775,856 Hauser Sept. 16, 1930 2,263,470 Perkins Nov. 18, 1,941 2,286,880 Traut June 16, 1942 2,333,100 Grant Nov. 2, 1943 

